CVE-2017-10755 in XnView Classic
Summary
by MITRE
XnView Classic for Windows Version 2.40 might allow attackers to cause a denial of service or possibly have unspecified other impact via a crafted .rle file, related to "Data from Faulting Address controls Branch Selection starting at ntdll_77df0000!LdrpInitializeThread+0x000000000000010b."
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Analysis
by VulDB Data Team • 10/22/2019
The vulnerability identified as CVE-2017-10755 affects XnView Classic for Windows version 2.40 and represents a critical denial of service condition that could potentially lead to more severe consequences. This flaw manifests when the application processes a specially crafted .rle file, which stands for Run-Length Encoded image format. The vulnerability specifically resides within the application's handling of malformed image data, where the processing logic fails to properly validate input parameters before executing critical operations. The issue stems from the application's failure to implement proper bounds checking and input sanitization mechanisms when parsing the RLE file format, creating a scenario where attacker-controlled data can influence the program's execution flow.
The technical exploitation of this vulnerability occurs through a specific code path within the ntdll component of the Windows operating system, specifically at the LdrpInitializeThread function where branch selection is influenced by data from a faulting address. This indicates that the vulnerability represents a classic case of indirect code execution control through memory corruption or manipulation. The flaw operates at a low level within the Windows kernel, where the application's image parser fails to properly handle malformed RLE data structures that ultimately corrupt the thread initialization process. This type of vulnerability aligns with CWE-125, which describes out-of-bounds read conditions, and CWE-248, which covers uncaught exceptions that result in unintended program behavior. The attack vector specifically leverages the application's insufficient validation of user-supplied data, creating an opportunity for attackers to manipulate memory access patterns and control program execution flow.
The operational impact of this vulnerability extends beyond simple denial of service, as it provides potential attackers with the capability to cause system instability and potentially achieve arbitrary code execution under certain conditions. When a user opens a maliciously crafted .rle file, the application crashes or becomes unresponsive, effectively rendering the image viewer unusable until the application is manually restarted. This denial of service condition can be particularly problematic in environments where XnView Classic is used for batch processing or automated image handling tasks, as it could lead to complete system outages or data processing interruptions. The vulnerability's potential for unspecified other impacts suggests that depending on the execution context and system configuration, attackers might be able to leverage this flaw for more advanced exploitation techniques, including privilege escalation or information disclosure. Organizations using XnView Classic in production environments should consider this vulnerability as a potential entry point for more sophisticated attacks, particularly in scenarios where users might encounter untrusted image files.
Mitigation strategies for CVE-2017-10755 should focus on both immediate defensive measures and long-term architectural improvements. The most effective immediate solution involves updating to a patched version of XnView Classic, as the vulnerability was addressed in subsequent releases through improved input validation and bounds checking mechanisms. System administrators should implement strict file type filtering and sandboxing measures for image processing applications, particularly when handling files from untrusted sources. Network-level controls can be implemented to block or scan .rle files before they reach end-user systems, reducing the attack surface. Additionally, organizations should consider implementing application whitelisting policies that restrict execution of potentially vulnerable applications unless explicitly authorized. The vulnerability demonstrates the importance of proper memory management and input validation in image processing libraries, aligning with ATT&CK technique T1059.007 for command and scripting interpreter, where the exploitation could potentially lead to further system compromise through command execution. Regular security assessments and vulnerability scanning should be implemented to identify similar issues in other image processing applications and prevent similar exploitation patterns.